Pyrene-tetrathiafulvalene supramolecular assembly with different types of carbon nanotubes

Pyrene-tetrathiafulvalenes reveal strong interactive forces with different types of carbon nanotube (CNT) samples-ranging from single-walled carbon nanotubes (SWNTs) to multi-walled carbon nanotubes (MWNTs). Notable, although subtle, are the differences that emerged while preparing, handling, and characterizing these composite materials. Stronger are the differences seen in the context of photoinduced charge transfer. In particular, charge injection into the conduction band of CNT probes afforded stable radical ion pair states (i.e., on the time scale of our femto/picosecond investigation) only for MWNTs, while the lifetimes for SWNTs are shorter. A likely rationale involves the multiple electron acceptor levels in MWNTs, when compared to SWNTs or double-walled carbon nanotubes (DWNTs).